mirror of https://github.com/0xERR0R/blocky.git
117 lines
2.5 KiB
Go
117 lines
2.5 KiB
Go
package lists
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"net"
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"net/http"
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"github.com/0xERR0R/blocky/config"
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"github.com/0xERR0R/blocky/evt"
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"github.com/avast/retry-go/v4"
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)
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// TransientError represents a temporary error like timeout, network errors...
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type TransientError struct {
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inner error
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}
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func (e *TransientError) Error() string {
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return fmt.Sprintf("temporary error occurred: %v", e.inner)
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}
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func (e *TransientError) Unwrap() error {
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return e.inner
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}
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// FileDownloader is able to download some text file
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type FileDownloader interface {
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DownloadFile(ctx context.Context, link string) (io.ReadCloser, error)
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}
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// httpDownloader downloads files via HTTP protocol
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type httpDownloader struct {
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cfg config.Downloader
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client http.Client
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}
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func NewDownloader(cfg config.Downloader, transport http.RoundTripper) FileDownloader {
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return newDownloader(cfg, transport)
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}
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func newDownloader(cfg config.Downloader, transport http.RoundTripper) *httpDownloader {
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return &httpDownloader{
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cfg: cfg,
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client: http.Client{
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Transport: transport,
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Timeout: cfg.Timeout.ToDuration(),
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},
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}
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}
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func (d *httpDownloader) DownloadFile(ctx context.Context, link string) (io.ReadCloser, error) {
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var body io.ReadCloser
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err := retry.Do(
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func() error {
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req, err := http.NewRequestWithContext(ctx, http.MethodGet, link, nil)
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if err != nil {
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return err
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}
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resp, httpErr := d.client.Do(req)
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if httpErr == nil {
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if resp.StatusCode == http.StatusOK {
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body = resp.Body
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return nil
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}
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_ = resp.Body.Close()
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return fmt.Errorf("got status code %d", resp.StatusCode)
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}
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var netErr net.Error
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if errors.As(httpErr, &netErr) && netErr.Timeout() {
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return &TransientError{inner: netErr}
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}
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return httpErr
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},
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retry.Attempts(d.cfg.Attempts),
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retry.DelayType(retry.FixedDelay),
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retry.Delay(d.cfg.Cooldown.ToDuration()),
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retry.LastErrorOnly(true),
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retry.OnRetry(func(n uint, err error) {
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var transientErr *TransientError
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var dnsErr *net.DNSError
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logger := logger().
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WithField("link", link).
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WithField("attempt", fmt.Sprintf("%d/%d", n+1, d.cfg.Attempts))
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switch {
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case errors.As(err, &transientErr):
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logger.Warnf("Temporary network err / Timeout occurred: %s", transientErr)
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case errors.As(err, &dnsErr):
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logger.Warnf("Name resolution err: %s", dnsErr.Err)
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default:
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logger.Warnf("Can't download file: %s", err)
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}
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onDownloadError(link)
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}))
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return body, err
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}
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func onDownloadError(link string) {
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evt.Bus().Publish(evt.CachingFailedDownloadChanged, link)
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}
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